It might have been merely a fleeting fad had the chenille creatures not recently landed on the shelves of mass retailers.

"For Christmas, my daughter wanted a Snuggie and a Pillow Pet, of all things," Angela Karp, a Stockton mother of two, said of her trendsetting daughter, who put in the request back in 2009 before they went mainstream. "She's the infomercial queen. She told me to try OxiClean."

As Karp's 6-year-old daughter, Sophia, compared Pillow Pets with her friends over after-school snacks Monday, Karp said the Pillow Pet does have its charms.

"They are good for car rides," she admitted. "And naps."

Pillow Pets have become popular snuggle buddies for kids of all ages. Although none would agree to go on the record for this story, even some boys have a Sir Horse, T-Rex, Chocolate Moose or Mr. Bear hanging out in their bedrooms.

And with Valentine's Day approaching, the creatures - there are more than three dozen to choose from - have conveniently welcomed a red heart-nosed cat and dog into the fold.

A San Diego mother of two came up with the concept for these cuddly companions.

Jennifer Telfer and her husband had grown tired of picking up the stuffed animals strewn across their children's rooms. What began with the simple goal of transforming a basic stuffed animal into a functional item for children has grown into a jungle of award-winning retail and wholesale products. Each folding stuffed animal features a strap of hook-and-loop tape to close it into a pet. Undo the strap and the critter flattens into a pillow.

Pillow Pets were sold mostly via that toll-free number flashing on TV commercials, online at mypillowpet.com, at kiosks and at specialty stores.

But six months ago, Pillow Pets became even more readily available.

Telfer said that's when the company partnered with its distributor to sell to mass market retailers including Bed, Bath and Beyond, Toys 'R' Us, and other big stores.

The kindergarten set is pretty straightforward about the appeal.

As they plopped down on the floor surrounded by their Pillow Pets, Sophia told her friends that she loves her pink and lavender Magical Unicorn because it's so cute. Her friend Alexa Myers, 5, likes lying on her new Hungry Hippo, because it is so soft. Sarina Chalk, 5, dresses her just-purchased Magical Unicorn up with hair accessories. And Gabriella Magnasco, 5, has not one but two Pillow Pets - that popular unicorn and Cuddly Bunny.

To illustrate how fads find fuel, Gabriella's 14-year-old sister, Alessandra, explained why the upper age brackets are now clutching these things.

"My friend Meghan texted all of us and told us she got one for Christmas, so we all had to get one, too," she said, speaking in that super-fast way teen girls like to talk.

Meghan O'Rourke, the instigator, admitted to succumbing to the commercial.

"I saw it on TV," the 13-year-old said, holding tight to her Lovable Ladybug. "I knew I just had to have one."

"It's your friend," Figueroa said, somewhat dramatically as she sent her friends into a spate of giggles. "You know it will be there for you."

But it didn't end there.

The Magnascos' 16-year-old sister, Stefania, coveted a Zippity Zebra. Of course her BFF had to have one, too.

And so on. And so on.

"It's like being a kid again," Stefania Magnasco said of why teens aren't immune. "They are so cute."

And unlike designer threads or other must-haves that teens covet, there's another appeal.

"You know, the price is attractive," their mom said of the toy's $19.99 tag. "It's not too expensive."

But now that she's purchased a few or more for her brood, she's seeing them everywhere.

Everywhere.

Moms report sixth-graders have taken them off to science camp. Preschoolers find them useful as nap buddies. School-age kids are sneaking them into backpacks. College kids toss them on dorm beds. And the owners of Toy Castle, in Stockton's Weberstown Mall, say even adults buy the Pillow Pets - get this - for themselves.

"I can't escape them," Lorene Magnasco said, laughing as she described how she spied two in the car seats of another mother's vehicle. "It's starting to become one of those Hitchcock movies where they are just turning up all over the place."

With 15 million sold so far, it's no wonder.

And the company has expanded its line to include Pillow Pet hats, blankets, backpacks, neck pillows and even slippers.

The invasion might still be incomplete.

As Alessandra Magnasco explained how she most definitely knows a boy who has a Pillow Pet of his own, her little sis and her friends dropped theirs and raced up the Karps' staircase to don princess costumes in Sophia's bedroom.